JPS6156963A - Electromagnetic induction flaw detection tester - Google Patents

Abstract

PURPOSE:To achieve a reduction in the equipment cost, by detecting flaws on the inner and outer surfaces of material to be detected in one line by an electromagnetic induction method. CONSTITUTION:An outer surface flaw detector 6 is made up of an external head 8 for holding an outer surface flaw detection sensor and an external stand 7 with a retreat/ lift/follow mechanism for the head 8 with respect to material 3 to be detected. On the other hand, an inner surface flaw detector 9 is made up of an internal head 10 for holding an inner surface flaw detection sensor while provided with a retreat/lift/follow mechanism for material 3. Also arranged are a support member 11 for supporting the head 10, a support roller 14 adapted to adjust the member 11 to the height of the center of the material, an inner surface support guide 13 existing in the material 3 to support the member 11 at the center of the material and a member 11 stopper mechanism for supporting the member 11 and the head 10. Then, material 3 is supplied to a conveying table 4 from a carry-in table 1 and upon the end of a flaw detection on the outer surface of the material 3, the material 3 is moved with a skew roller 5. A flaw detection on the inner surface is done with the internal head 10 and upon the end of the detection, the material 3 is ejected out to a carry-out table 2.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to the advancement of spirally conveyed steel pipes.

The present invention relates to a flaw detection test device that uses electromagnetic induction to detect flaws on the inner or outer surface during retreat.

[Conventional technology]

In recent years, quality assurance for steel pipes has been significantly strengthened as customer requirements have become more sophisticated. Ultrasonic flaw detection is generally used as a means of quality assurance. However, a single flaw detection method does not provide quality assurance that satisfies the customer's requirements, and there is an increasing trend toward so-called complex testing, in which two or more types of non-destructive testing are applied. In other words, in the ultrasonic flaw detection method, the influence of the direction of the flaw is easily affected (for example, if you create an artificial flaw that is tilted with respect to the tube axis direction and examine its detection limit, -5d・b
The allowable angle is ±5°. For this reason, in manufacturing processes where a slope rate occurs due to the characteristics of pipe manufacturing, it may not be possible to detect defects depending on their directionality using ultrasonic flaw detection alone. Therefore, it is up to □ that multiple tests are being carried out.

In making inspection more complex, it is necessary to inspect not only external defects but also internal defects at the same level over the entire surface and length of the material to be inspected. Conventionally, as a technique for this purpose, an electromagnetic induction flaw detection method is used in addition to an ultrasonic flaw detection method. This electromagnetic induction flaw detection method detects defects by placing an inspection coil near the material to be inspected, passing an alternating current through the coil, and checking the electromagnetic response of the coil.

If a defect exists, the eddy current generated in the material under test changes, and this change in eddy current changes the electromagnetic response of the coil, so detecting the electromagnetic reaction can identify defects in the material under test. This makes detection possible.

Conventional electromagnetic induction flaw detection method is used for external inspection.
The surface flaw detection sensor and detection stand are fixed, and the material is conveyed in a spiral to inspect the entire surface and length of the material being inspected. On the other hand, in the case of internal surface inspection, the entire surface and length of the internal surface is inspected by rotating the material to be inspected with a turning roller and moving the internal flaw detection sensor back and forth in a straight line over the entire length of the material to be inspected. . That is, in the case of this inner surface inspection, the material to be inspected was not conveyed in a spiral manner.

[Problem that the invention seeks to solve]

However, in the conventional electromagnetic induction flaw detection method, the method of transporting the material to be inspected and the scanning method of the internal and external flaw detection sensors are completely different, so completely separate equipment is required. Therefore, the equipment cost is very high and a large amount of installation space is required.

In addition, a detection sensor for internal inspection is supported at the tip of a rod-shaped support member. The support member is cantilevered. Therefore, when the material to be tested is long, the support member also becomes long depending on the material to be tested, making it difficult to support the skin. In other words, as the support member becomes longer, unless the strength of the support member itself is increased, the support member will bend in the middle, and it is necessary to increase the diameter of the support member. Therefore,
Conventional internal surface inspections were limited by equipment and could only be applied to large diameter and short lengths.

For this reason, in conventional internal surface inspection, when inspecting a long material to be inspected, two internal surface inspection devices are installed together, and one device inspects the material from one end to the center. inspect,
Thereafter, the device on the other side inspected the material to be tested from the other end to the center.

Therefore, there are drawbacks such as higher equipment costs and a larger installation space.

In short, in the conventional electromagnetic induction flaw detection method, the inner and outer flaw detection equipment must be completely separated, and when inspecting long materials, the inner flaw detection equipment must be used twice. The drawback was that a stand had to be installed.

[Means for solving problems]

In view of the above-mentioned drawbacks of the conventional electromagnetic induction flaw detection method, the present invention improves and eliminates them. The gist of it is:
This is a flaw detection test device using an electromagnetic induction method that detects flaws on the inner and outer surfaces of a spirally conveyed steel pipe using an inner surface flaw detection device and an outer surface flaw detection device. , an outer surface stand equipped with an evacuation elevating and following mechanism for the material of the outer surface head; a head, a support member that supports the inner head, a support roller that adjusts the support member to a height at the center of the material, an inner support guide that is within the material and supports the support member at the center of the material, and the support member and a stopper mechanism for a support member that supports an inner surface head.

The present invention aims to significantly reduce equipment costs and save equipment space by providing the above-mentioned electromagnetic induction flaw detection testing device, which enables the detection of defects on internal and external surfaces in one line. The configuration of the inventive device will be described in more detail below based on the embodiment shown in the drawings.

〔Example〕

Fig. 1 is a plan view showing the overall arrangement of the embodiment device;
The figure is a schematic side view showing the main parts of the device. In the figure, 1 is a table for carrying in, and 2 is a table for carrying out. A conveyance table 4 for conveying the material to be inspected (in this embodiment, a seamless steel pipe of 100 to 280 fi'') 3 is installed between the loading and unloading tables 1 and 2. The table 4 has a length more than twice that of the material to be tested 3, and rollers 5 are installed at predetermined intervals to spirally transport the material to be tested 3. As shown in Fig. 2, it is an external surface flaw detection device that is supported from a stand 7.
WJ'''y F 8 'lr* b '''Cpa Z・00
1 to 8 are located above the material to be inspected 3 being conveyed on the table 4, and can move up and down and follow the material to be inspected 3. This will be described later.

Further, on the front end (right end in FIG. 1) side of the conveyance table 3, there is a support member 11 that supports the inner surface head 10 of the inner surface flaw detection device 9.
Stand E 2 has been installed. The inner surface head 10 and the support member 11 are mounted so that their centers coincide with the center of the test material 3 being transported on the transport table 4.

In the middle of the support member 11, there is an inner support guide 13,
A support roller 14 is attached. The inner surface support guide 13 is located within the material 3 to be tested and is for supporting the support member 11 at the center of the material, and the support roller 14 is
This is for supporting the support member 11 centered on the material when there is no material 3 to be tested.

Next, the configuration of each of the above members will be explained in more detail.

First, the external surface flaw detection device 6 will be explained. As shown in FIG. 3, this device 6 has an external stand 7 erected near the conveyance table 4, and an external spatula 8 is attached so that it can be moved up and down, depending on the outer diameter of the material. Height adjustment is possible. To move the external head 8 up and down, the rad 8 is screwed onto the external surface of the screw rod 15.
This is achieved by transmitting 60 rotations of the lifting motor to the screw rod 15 via bevel gears 17 and 18.

FIG. 4 is a half sectional view showing a part of the sensor and the retraction following part of the outer surface of the radar 8. 19 is a head body formed in a box shape. A magnet 20 is fixed within this head body 19, and a moving coil 21 is arranged above it. Reference numeral 22 denotes a guide pipe that passes through the center cavity of the magnet 20 and the moving coil 21 and projects downward from the head body 19. A distance sensor 23 and an external flaw detection sensor 2 are provided on the lower end side of this guide pipe 22.
A sensor holder 25 for holding 4 etc. is attached. Further, the moving coil 21 is attached to the upper end side of the guide pipe 22. Reference numeral 26 denotes a guide for the sensor holder 25, and has a slide unit 28 that fits onto the magnet box 27 inside the head body 19. 29 is a neutral point holding spring, and 30 is a horizontal holding spring for the sensor holder 25. The horizontal holding spring 30 is a so-called collision prevention spring that moves up and down by the amount of deformation when the material 3 to be tested is thick (deformed).

The moving coil 21 is a so-called electromagnet. When this is excited, magnet 2o and magnet pock 2
7 causes the sensor holder 25 to move. The direction of movement is controlled by the direction of the excitation current. FIG. 4 shows this state. When the moving coil 21 is de-energized, the sensor holder 25 is stopped at a point where the tensile force of the neutral point holding spring 29 and the weight of the holder are balanced. Now, when the maximum upward current is applied, the guide 26 and the sensor holder 25 are drawn upward. In other words, it is in a non-inspection state. The slide unit 28 is for stably performing this raising and lowering operation. During the inspection,
Follow-up control is performed while maintaining a constant gap by feeding back the distance signal from the distance processor 23.

Next, the inner surface head 10 of the inner surface flaw detection device 9 will be explained with reference to FIGS. 5 and 6.

This inner head 10 is formed by a frame 31
Semi-cylindrical shoes 32 are attached to the top and bottom of both ends, respectively, and are slidable on the inner circumferential surface of the test material 3. shoe 3
2 is such that a predetermined clearance is formed between it and the inner circumferential surface of the upper end of the material 3 to be tested. This is test material 3
If the inner head 10 is bent, the inner head 10 cannot move straight, so this is to avoid this. frame 31
A solenoid box 33 is fixed inside. 3
4 is an operating rod of the solenoid 35, which projects downward from the solenoid box 33 so as to be able to rise and fall freely. 36 is a sensor holder attached to the lower end side of the operating rod 34; 37
is a slide unit that is slidably fitted onto the solenoid box 33. It goes without saying that an internal flaw detection sensor (not shown) is built into the sensor holder 36. Sensor box 33 and sensor:;
A spring 38 is attached between the sensor holder 36 and the sensor holder 36 to cause the sensor holder 36 to follow the shape of the inner peripheral surface of the material 3 to be tested.

When the solenoid 35 is in a non-energized state, the sensor holder 36 is urged downward by the spring 38 and is in contact with the inner circumferential surface of the material 3 to be tested. In other words, it becomes an inspection state. FIGS. 5 and 6 show this state. Further, when the solenoid 36 is in an excited state, the operating rod 34 is drawn upward, and the sensor holder 36 is moved away from the inner circumferential surface of the material to be tested 3 and placed in a retracted state.

7 and 8 show the stand 12 and the stopper mechanism 39 of the support member 11 of the inner surface flaw detection device 9. FIG. The stand 12 has two posts 40 and 41, and the support member 11 is supported through the posts 1-40 and 41 so as to be able to move up and down. The stopper mechanism 39
It has guide rods 42,43 fixed at 0°41. Reference numeral 44 denotes a fixed frame mounted across the guide rods 42 and 43. This fixed frame, M44
A screw rod 46 with a pan 45 passes through the bolt. Reference numeral 47 denotes a movable base attached to the lower end of this rod 46, and the guide rods 42 and 43 are attached to both ends of the movable base.
is penetrated. The support member 11 is attached to this movable table 47.
It penetrates and is fixedly supported.

Therefore, by rotating the handle 45, the rod 46 moves up and down with respect to the fixed frame 44, and the movable base 47
to raise and lower. That is, the support member 11 is moved up and down. 4
Reference numeral 8 denotes a scale plate that indicates the height position of the support member 11 during this lifting and lowering operation.

FIG. 9 shows the inner surface support guide 13 mounted and fixed in the middle of the support member 11. As shown in FIG. This inner support guide 1
3 has an outer diameter that is approximately the same as the inner diameter of the material to be inspected 3, and comes into contact with the inner circumferential surface of the material to be inspected 3 to support the support member 11 when detecting defects on the inner surface. In this embodiment, the inner surface support guide 13 is split in half and attached to the support member 11 from above and below.

FIGS. 10 and 11 show a support roller 14 that supports the midway downward part of the support member 11 when there is no material 3 to be tested, and aligns its center with the center of the material.

This support roller 14 is rotatably mounted astride the upper end of the post 50.51. The rotation is performed by an air cylinder 52. 53 is a locking member fixed to the rotation shaft 54 of the support roller 14, and 55 is a stopper for determining the rotation stroke of the support roller 14. When the air cylinder 52 is moved to a position where the locking member 53 comes into contact with the stopper 55, the support roller 14 rotates to the position shown by the chain line in FIG. 10 and supports the support member 11 below.

In other words, the support roller 14 can support the support member 11 midway, and the support member 11 will not be bent midway. .

Next, the operation mode of the electromagnetic induction flaw detection testing apparatus configured as described above will be explained.

Before the start of flaw detection, the external head 8 is in a standby position at an upper position due to the tensile force of the neutral point holding spring 29. Further, the support roller 14 supports the intermediate portion of the support member 11 from below.

When the test material 3 is supplied from the carry-in table 1 to the transport table 4 by a picker (not shown) from this state, the test material 3 is rotated in a spiral by the skew roller 5 from the left side to the right side in FIG. Start moving towards.

When the tip of the test material 3 reaches the outer stand 7, the moving coil 21 of the outer head 8 is excited.
The sensor holder 25 starts tracking the outer circumferential surface of the material 3 to be inspected at a constant gap (0.3 m in this example), and starts detecting defects using the electromagnetic induction method. In this case, if there is a change in height on the outer peripheral surface of the test material 3, the sensor holder 25 uses the distance sensor 23 to detect and follow the change in height. The follow-up stroke in this example is within a range of ±10 wm from the neutral point. When the flaw detection on the outer surface of the material to be inspected progresses and the leading edge of the material reaches the position of the support roller 14, the air cylinder 52 shown in FIG. 10 moves back and forth, and the support roller 14 rotates to the position shown by the solid line in the figure. . That is, it retreats to a position where it does not interfere with the test material 3. When the tip of the material 3 to be tested reaches the position of the inner surface support guide 13, the guide 13 is inserted into the material 3 to be tested and supports the intermediate portion of the support member 11 within the material.

1! When flaw detection on the outer surface of the material to be inspected is completed in this manner, the moving coil 21 of the outer surface head 8 enters an upwardly retracted energized state, and the sensor holder 25 rises and stands by. At the same time, the skew roller 5 starts to rotate in reverse, and the material 3 to be tested is rotated in a spiral manner while being conveyed backward from the right side to the left side in FIG.

At the same time, electromagnetic induction flaw detection for internal flaws is performed using the inner surface head 0. This inner surface flaw detection is performed by de-energizing the solenoid 35 and bringing the sensor holder 36 into contact with the inner circumferential surface of the material 3 to be inspected by the biasing force of the spring 38. In the case of this inner surface flaw detection sensor holder 36 as well, if there is some unevenness on the inner peripheral surface of the material, it moves up and down within the elastic range of the spring 38 to avoid and follow the unevenness. And test material 3
When the pipe end passes the position of the support roller 14, the air cylinder 52 shown in FIG. . Thereby, the center of the support member 11 can always be aligned with the center of the material. After the tube end of the material 3 to be inspected passes through the inner surface head 10 and the inner surface flaw detection is completed, the solenoid 35 shown in FIG. 5 is energized, and the sensor holder 36 is pulled upward and placed on standby.

The material 3 to be tested whose inner and outer surfaces have been inspected for flaws is kicked out to the carry-out table 2 by a kicker (not shown).

Thereafter, by repeating the above-described operations, defects on the outer surface and inner surface of the test material 3 are sequentially detected. For reference, in the apparatus of this example, the inner and outer surfaces of a hot-worked seamless steel pipe with a diameter of 180 m and a length of 14 m were each inspected for flaws using four sensors. The time required for flaw detection was 5 minutes.

FIG. 12 is a block diagram showing the signal processing method of the apparatus of this embodiment. It is output from the external head 8.

The external surface flaw detection signal a is discriminated between a defect signal and noise by an external surface flaw discrimination circuit A, and is sent to the next flaw determination and marking control circuit. If there is an unacceptable flaw, a marking signal C is output to the outer surface flaw marker 58, and marking is performed on the outer circumferential surface of the material 3 to be inspected. In the case of internal flaw detection, selector switch 58.57
is automatically switched to the opposite side of FIG. The inner surface flaw detection signal output from the inner surface head 10 is discriminated between defects, noise, etc. by an internal flaw discrimination circuit B. Then, for unacceptable flaws, a marking signal d is sent from the circuit to the inner surface flaw marker 59, and marking is performed on the outer circumferential surface of the material 3 to be inspected.

Next, the case of changing the loft will be explained. In this case, first,
The shoe 32 of the inner surface head 10 is replaced with one corresponding to the inner diameter of the material 3 to be tested. Then, the handle 45 shown in FIGS. 7 and 8 is operated to raise and lower the movable base 47, and the center of the support member 11 fixedly supported by the movable base 47 is aligned with the center of the material. Also, the inner surface support guide 13 fixed in the middle of the support member 11 is replaced with one corresponding to the inner diameter of the material to be tested. Finally, the stopper 5 shown in FIGS. 10 and 11
The rotating stroke of the support roller 14 may be adjusted by adjusting the threaded state of the support roller 14 so that the support roller 14 comes into contact with the lower part of the test material 3 that has been changed in lot. The external head 8 only needs to adjust the height of the sensor holder 25 to be flush with the top surface of the test material using the lifting motor I6.

〔Effect of the invention〕

As explained above, in the present invention, defects can be detected by electromagnetic induction on the inner and outer surfaces of the test material in one line, and there is no need to provide separate lines for the inner and outer surfaces as in the past. Therefore, equipment costs can be significantly reduced.

Furthermore, less equipment space is required, allowing for effective use of space. In addition, since flaw detection on the inner and outer surfaces can be performed while the test material is reciprocating, the flaw detection time can be significantly shortened.

[Brief explanation of drawings]

Fig. 1 is a plan view showing the overall arrangement of the embodiment device, Fig. 2 is a schematic side view showing the main parts of the device, Fig. 3 is a partial longitudinal sectional view of the external flaw detection device, and Fig. 4 is the external head. 5 is an enlarged view of the inner head; FIG. 6 is a half sectional view of the inner head taken in a direction perpendicular to the tube axis; FIG. 7 is a half sectional view of the inner head; A side view showing the mechanism, FIG. 8 is a rear view of the same mechanism, FIG. 9 is a sectional view showing the inner support guide, FIG. 10 is a side view showing the support roller, FIG. 11 is a rear view of the support roller, 12th
The figure is a block diagram showing an example of signal processing of the embodiment device. 3... Material to be tested 6... External flaw detection device 9...
・Inner surface flaw detection device 8...Rad to outer surface 7...Outer surface stand 10...Inner surface head 11...Support member
14...Support roller 13...Inner support guide 39...Stopper mechanism patent applicant Sumitomo Metal Industries Co., Ltd. Agent Toshihiko Uchida, patent attorney Figure 3 Figure 4 Figure 10 Figure 11

Claims (1)

[Claims] 1. A flaw detection test device using an electromagnetic induction method that detects flaws on the inner and outer surfaces of a spirally conveyed steel pipe using an inner surface flaw detection device and an outer surface flaw detection device, the outer surface flaw detection device including an outer surface head holding an outer surface flaw detection sensor; The inner surface flaw detection device includes an outer stand having an evacuation elevating and following mechanism for the material of the outer surface head, and an inner surface stand that holds an inner surface flaw detection sensor and is equipped with an evacuation elevating and following mechanism for the material; A support member that supports the head, a support roller that adjusts the support member to a height at the center of the material, an inner support guide that is within the material and supports the support member at the center of the material, and a support that supports the support member and the inner head. An electromagnetic induction flaw detection testing device characterized by comprising a stopper mechanism for a member.